PCB Inspection Guidelines

As electronic components become more complex and dense, in smaller packages, the need for X-ray and Real-time X-ray inspection is increasing for use in failure analysis and in production. Real-time X-ray technology can be used to determine if there is a short between two or more pins in a device. FPGAs are dense devices that uses a high count of pins in a typical BGA package with fine pitches.

Set a limit of 15 rads using a zinc filter tray of exposure from a real-time X-ray source to avoid damaging the programming circuitry of IGLOO2 and SmartFusion2 FPGAs. At higher doses than 15 rads there is a higher risk that the device fails to program, device ages and could potentially have retention issues.

Tube voltage, power, current, duration, distance, and filter (shielding) all impact real-time X-ray radiation dose. In testing, a Quadra 7 Real-Time X-ray Inspection system from Nordson DAGE is used.

For questions or more details, email aviation@microchip.com.